CHAPEL HILL -- Children who survive a condition at birth in which their lungs are too stiff to saturate their blood with enough oxygen may be at increased risk for progressive hearing loss and need periodic hearing tests, according to a University of North Carolina at Chapel Hill physician. Newborns with the potentially life-threatening condition called persistent pulmonary hypertension, or PPHN, usually are put on mechanical ventilation via a breathing tube.
Survivors of PPHN need follow-up monitoring with periodic hearing tests, even if standard auditory testing in the first weeks of life prove normal, according to Dr. Wendell G. Yarbrough, assistant professor of otolaryngology and head and neck surgery at the UNC-CH School of Medicine. In the United States, about 10,000 babies a year are born with this disorder.
Writing in the August issue of the Archives of Otolaryngology, a journal of the American Medical Association, Yarbrough makes his point describing the case of a child with delayed-onset hearing loss.
"As a newborn, this child had survived persistent pulmonary hypertension. He was treated in neonatal intensive care and after discharge from the hospital had done fine on regular pediatric examinations," Yarbrough explained. "He also did well on standard developmental tests at seven and 13 months. These showed normal response to sound, but did not include formal audiologic testing.
"But when he was about 3 years old, his parents brought him to our clinic because they were concerned that the child might have poor hearing. They had noticed the difference in speech development between their older child." The parent's concerns were justified. The child communicated with poor articulation, and hearing tests revealed moderate to severe bilateral sensorineural hearing loss. Auditory structures within his ears essentially were not detecting sound signals for nerve transmission to the brain.
"We fitted him with hearing aids and sent him to speech pathology for a formal speech and language evaluation. He had a vocabulary of about 50 words, compared with 900 words typical of 3 year olds," Yarbrough said. "Auditory comprehension, expressive communication and total language score were consistent with a one-year delay in speech and language skills."
The boy was enrolled in speech therapy and followed by an audiologist for hearing evaluation and refitting of hearing aids. When he was seen again in the clinic six months later, his vocabulary had increased to 250 words. But tests demonstrated a progression in hearing loss.
In his journal report, Yarbrough acknowledged a growing body of data supporting a link between PPHN, its medical treatment and hearing loss.
"The issue is clouded to some degree because a lot of these children were on different types of ventilation support or on drugs such as gentamycin [an antibiotic], which have been associated with hearing loss," he said. "But I think it's becoming clearer that the underlying insult is not necessarily what we do to the child but the disorder itself, PPHN."
Still, Yarbrough said, it's time that doctors and the public acknowledge that a link may exist between PPHN and subsequent hearing loss.
"We recommend that children with a history of PPHN receive audiologic evaluations every six months until the age of 3 years to avoid the morbidity and tremendous cost to society associated with a delayed diagnosis of hearing loss," he said. "If hearing loss is detected early, the child can be [hearing] aided.
"And we think parents of children who survived PPHN should be informed about the limitations of neonatal screening and advised to be aware of symptoms of speech and language delay," he added. "The earlier the intervention, the better the speech development, cognitive development and school performance."
By LESLIE LANG
UNC-CH School of Medicine
Note to media: Dr. Wendell "Dell" Yarbrough can be reached at 919-966-3341 or wgy@med.unc.edu
Journal
Archives of Otolaryngology